Aircraft have air conditioning (AC) systems for providing conditioned air for crew and passenger. AC systems have one or more exhaust air outputs which commonly comprise exhaust silencers. Such silencers are arranged to reduce the noise of the AC exhaust air output and need also to cope with significant thermal loads.
Aircraft AC exhaust silencers are traditionally made from high specification aerospace metals such as Titanium or Aluminium alloys in enable them to cope with an appropriate range of operating temperatures. As a result, aircraft AC exhaust silencers are expensive, heavy and complex to manufacture.